Among his most significant achievements are the development of timing attacks that can break implementations of RSA, DSA and fixed-exponent Diffie–Hellman that operate in non-constant time, as well as the co-development of power analysis and differential power analysis. He also contributed to the design of Deep Crack, a DES brute-force key search machine. He was one of the architects of the Secure Sockets Layer (SSL) 3.0 protocol, a cryptographic protocol for secure communications on the Internet.